The present invention relates to implants and associated bone preparation instrumentation for use in joint replacement surgery. Knee arthroplasty is a known type of orthopaedic procedure typically aimed at correcting a patient condition through the implantation of a unicompartmental, bi-compartmental or tri-compartmental implant. In standard tri-compartmental or total knee arthroplasty, orthopedic implants replace areas of resected cartilage and bone on the distal femoral and proximal tibial bone. Typically, such an orthopaedic implant system may include a femoral component, a tibial component and a tibial insert that is assembled to the tibial component. Current tibial insert designs feature contoured articular surfaces designed to articulate with the femoral component. The respective geometries of the articular surface and femoral component are designed to result in a patient having a more “normal feeling” knee replacement. An example of such an insert design is described in U.S. Pat. No. 7,160,330, titled “Emulating Natural Kinematics in a Knee Prosthesis,” which is hereby incorporated by reference herein. The evolution of these current designs focus on load transfer and kinematics between the femoral component and tibial insert. However, the bone contacting surface of the tibial baseplate has not been modified relative to the insert geometries. Therefore, while load transfer characteristics and function may be improved between the femoral implant and insert, the subsequent load transfer between baseplate and patient bone remains as a cooperation of simple planar contacting surfaces.
Loosening of a tibial baseplate is a well documented failure mode in orthopaedic registries for knee arthroplasty. The cause of baseplate loosening is multifactorial, but may in part be attributed to the various loads transferred to the tibial baseplate and bone contacting surface. Limitations in bone preparation instrumentation have kept the tibial baseplate bone contacting surface relatively planar, and any inaccuracies in bone preparation may lead to rocking, and eventually loosening of a tibial baseplate once implanted. As such, accuracy of preparation is a concern for both cemented and cementless implant designs, with cemented designs potentially being slightly more forgiving given the degree of correction of inaccurate bone cuts such cemented designs may provide.
Thus, there exists a need for a tibial baseplate with an increased resistance to tibial bone interface loading, as well as instrumentation for facilitating implantation of same.